How do Summon Monster spells work from lore perspective?

Context: I plan on GM’ing a long campaign in MtG universe. Most of my players will become planeswalkers at some point (full-progression casters rules-wise) and will travel throughout universe a lot.

This is when I realized that I completely lack knowledge on how the bread-and-butter part of MtG universe really works, which is summoning. In D&D this comes down to a simple series of spells: Summon Monster, and variants of it. And this is what I want to focus on here.

My problem with Summon Monster comes down to several key aspects of it that are not described in D&D rulebooks. All of those aspects have a source in a single question: whether what is summoned is actually a creature from another plane or just copy of it, magical dummy that does what it was told to and vanishes?

If it’s indeed a creature from another plane being summoned (which most opinions around the web seem to point at) this raises a series of storytelling problems, established lore plot-holes and power level concerns. I’ll try to list those issues here:

  1. How are creatures to be summoned chosen? Can every creature in universe that has an outsider type be summoned? Can players playing tieflings and aasimars be summoned too?
  2. Does a summoned creature have a say in whether it wants to be summoned in the first place? Can You just pull a creature out of it’s own plane at any moment in time? As funny as it sounds, majority of summoning situations would be either during eating, pooping, sleeping or having the fun-time. Not exactly pretty picture.
  3. It also raises another concern. Whatever the creature was doing at the time of summoning is left unattended. This means summoning have a potential of mass destruction, simply by pulling out guards off their posts, builders off their work, sailors off their ships, etc.
  4. Does a summoned creature have a say in whether it wants to follow orders? Can You keep sending let’s say celestial creatures against their own kin? If that’s the case conquering other planes would be as simple as summoning half of it’s inhabitants to fight the other half.
  5. Last but not least there’s a power level issue. From the perspective of simple combat situation Summon Monster seems like an average spell. Gives a temporary meatshield so caster can focus on casting instead of running from enemy. But when You look from the perspective of all I mentioned above, this is basically a planar travel combined with mind control, both of which are high-level endeavors. How can a low-level caster accomplish something like that?

So with all of the above in mind, I’m asking for a comprehensive, detailed description of how Summon Monster spells work in D&D or MtG or both (since after WotC married the too there are intersections) that addresses all or most of the issues I listed above.

I’m only interested in official content (for example official D&D rulebooks/setting books, official D&D novels, official MtG novels).

I’m also aware this is a very complex topic and I might not worded it perfectly so if someone wants to edit the question to be better, feel free to do so.